DE102014112093A1 - Test System for an Oxidation Catalyst / Hydrocarbon Injector - Google Patents

Abstract

An oxidation catalyst (OC) / hydrocarbon injector (HCI) testing system includes a controller having a first oxygen sensor input configured and arranged to receive a first oxygen sensor value upstream of an oxidation catalyst / OC device, and a second oxygen sensor value Oxygen sensor input configured to receive a second oxygen sensor value downstream of the OC device. The controller is configured and arranged to perform a first test based on a difference between the first and second oxygen sensor values to detect a faulty OC device or a faulty HCI.

Description

FIELD OF THE INVENTION

The present invention relates to motor vehicles, and more particularly, to an oxidation catalyst (OC) and a hydrocarbon injector (HCI) inspection system.

BACKGROUND

Exhaust gas expelled from an internal combustion engine represents a heterogeneous mixture that contains gaseous emissions such as, but not limited to, carbon monoxide ("CO"), unburned hydrocarbons ("HC") and nitrogen oxides ("NOX _x "). as well as condensed phase materials (liquids and solids) that form particulate matter ("PM"). Catalyst compositions typically disposed on catalyst carriers or substrates are provided in an engine exhaust system as part of an aftertreatment system to convert some or all of these exhaust constituents to unregulated exhaust gas components.

One type of exhaust treatment technology for reducing emissions is a particulate filter ("PF"). The PF is designed to remove diesel particulate matter or soot from the exhaust of an engine. The particulate matter that is removed from the exhaust gas is trapped by and loaded into the PF. When accumulated soot reaches a predetermined level, the PF is either replaced or regenerated. Replacement or regeneration ensures that soot removal will stop at desired parameters. In addition, many engines have an oxidation catalyst ("OC") that oxidizes hydrocarbons and carbon monoxide to carbon dioxide and water to further reduce emissions.

In certain arrangements, a motor vehicle may also include a hydrocarbon injector (HCI) that introduces hydrocarbons into exhaust gases to raise an exhaust gas temperature. Increasing the exhaust gas temperature heats the OC to improve catalytic performance. The introduction of hydrocarbons and added heat also reduces the build-up of contaminants in the OC and the PF. Failure of the HCI is often misdiagnosed as an error of the OC. An unnecessary replacement of the OC is an expensive and time-consuming process that can lead to customer dissatisfaction. Accordingly, it is desirable to provide a test system that can more accurately detect a faulty HCI. In addition, it is desirable to provide a test system that can distinguish between a faulty HCI and a faulty OC.

SUMMARY OF THE INVENTION

In an exemplary embodiment, an oxidation catalyst (OC) / hydrocarbon injector (HCI) inspection system includes a controller having a first oxygen sensor input configured and arranged to provide a first oxygen sensor value upstream of an oxidation catalyst (OC) device and a second oxygen sensor input configured to receive a second oxygen sensor value downstream of the OC device. The controller is configured and arranged to perform a first test based on a difference between the first and second oxygen sensor values to detect a faulty OC device or a faulty HCI.

According to another exemplary embodiment, an automotive exhaust system includes a hydrocarbon injector (HCI) configured to introduce hydrocarbons into the exhaust system, an oxidation catalyst (OC) device located downstream of the HCI, a first oxygen sensor, located upstream of the OC device, a second oxygen sensor disposed downstream of the OC device, and an oxidation catalyst (OC) / hydrocarbon injector (HCI) inspection system. The OC / HCI test system includes a controller having a first oxygen sensor input operatively connected to the first oxygen sensor. The first oxygen sensor input is configured and arranged to receive a first oxygen sensor value. A second oxygen sensor input is operatively connected to the second oxygen sensor. The second oxygen sensor input is configured to receive a second oxygen sensor value. The controller is configured and arranged to perform a first test based on a difference between the first and second oxygen sensor values to detect a faulty OC device or a faulty HCI.

In yet another exemplary embodiment, a method of monitoring an oxidation catalyst (OC) device and a hydrocarbon injector (HCI) in an exhaust system includes detecting a first oxygen sensor value at a first oxygen sensor located upstream of the OC device Detecting a second oxygen sensor value at a second oxygen sensor downstream of the OC device calculating a difference between the first oxygen sensor value with the second oxygen sensor value and performing a first test to determine whether the OC device or the HCI is faulty based on the difference between the first oxygen sensor value and the second oxygen sensor value.

The above features and advantages as well as other features and advantages of the invention will be readily apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features, advantages, and details will become apparent, by way of example only, in the following detailed description of embodiments, the detailed description of which refers to the drawings, in which:

1 Figure 3 is a perspective view of a portion of an automotive exhaust system including an oxidation catalyst (OC) / hydrocarbon injector (HCI) testing system in accordance with an exemplary embodiment;

2 is a block diagram showing the test system of 1 shows; and

3 FIG. 10 is a flowchart illustrating a method of monitoring an OC device and an HCI according to an example embodiment.

DESCRIPTION OF THE EMBODIMENTS

The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. It should be understood that in the drawings, like reference numerals indicate like or corresponding parts and features. An exhaust system according to an exemplary embodiment is shown in FIG 1 generally with 2 shown. The exhaust system 2 is provided with a plurality of emission reduction devices comprising a metal oxidation catalyst (MOC) device 4 fluidly with a device 6 for selective catalytic reduction (SCR), a hydrocarbon injector (HCI) 8th and an oxidation catalyst (OC) device 10 exhibit. More specifically, the MOC device 4 an inlet 12 on, with an exhaust manifold of a motor vehicle (not shown) by a turbocharger 13 can be connected. The MOC device 4 also has an outlet 14 fluidly with an inlet 16 the SCR device 6 through a first exhaust pipe 18 connected is. A urea injector 20 can be between the MOC device 4 and the SCR device 6 be arranged. The SCR device 6 has an outlet 23 on, the fluid technically with the HCI 8th connected is. The HCI 8th has an outlet 29 on, passing through a second exhaust pipe 34 fluidly with an inlet 32 the OC device 10 can be connected. The OC device 10 has an outlet 36 on, which leads to the environment. The outlet 36 may lead to the environment through a particulate filter (not shown).

The exhaust system 2 also has a first oxygen sensor 44 which is upstream of the HCI 8th is arranged, and a second oxygen sensor 46 on, the downstream of the HCI 8th is arranged. In the exemplary embodiment shown, the first oxygen sensor is 44 upstream of the SCR device 6 arranged and the second oxygen sensor 46 is downstream of the OC device 10 arranged. The exhaust system 2 also has a first temperature sensor 48 , which is upstream of the OC device 10 is arranged, and a second temperature sensor 50 on, the downstream of the OC device 10 is arranged. The first temperature sensor 48 is also downstream of the HCI in the exemplary embodiment shown 8th arranged. It should be noted here that the respective location of the first and second oxygen sensor 44 and 46 and the first and second temperature sensors 48 and 50 can vary. It should also be understood that the number of oxygen sensors and temperature sensors may vary.

Over time, and through continued use, the HCI 8th and / or the OC device 10 begin to fail. In the case of HCI 8th The internal parts begin to wear or clog, resulting in a reduction in function. The OC device 10 may be subject to washcoat degradation resulting in a reduction in operating efficiency. Often a faulty HCI 8th be misdiagnosed as a defective OC device. According to an exemplary embodiment, the exhaust system 2 a test system 80 for Oxidation Catalyst / Hydrocarbon Injector (OC / HCI), 2 , on. The OC / HCI test system 80 has a controller 84 which, as explained in more detail below, performs a number of checks between defective OC devices and defective HCIs 8th different. The control unit 84 may be part of automotive controls (not shown) or may be embodied in a separate portable device (also not shown).

As in 2 shown has the OC / HCI test system 80 a control unit 84 with a central processing unit (CPU) 86 and a memory 88 on. As will be better described below, the memory stores 88 a first threshold 90 and a second threshold 91 , The respective value of the first and second thresholds 90 and 91 may depend on the manufacture and model type of the OC device 10 vary. The control unit 84 also has a first filter 93 and a second filter 94 on. The first filter 93 is used to determine the reaction time of the first and second oxygen sensors 44 and 46 adjust. More specifically, the first oxygen sensor 44 faster than the second oxygen sensor 46 respond to the oxygen content in through the exhaust system 2 to change flowing exhaust gases. The first filter 93 supports a more accurate mathematical comparison of data from each oxygen sensor 44 . 46 , The second filter 94 is from the controller 84 used to measure the distance between the first and second oxygen sensors 44 and 46 to take into account.

Further, the controller 84 shown to have a first oxygen sensor input 96 that works with the first oxygen sensor 44 connected, and a second oxygen sensor input 97 which is functional with the second oxygen sensor 46 connected is. The control unit 84 also has a first temperature sensor input 99 that works with the first temperature sensor 48 connected, and a second temperature sensor input 100 on, which is functional with the second temperature sensor 50 connected is. The control unit 84 still has an exit 108 on, the functional with a display 110 is coupled. the display 110 may represent a light on an instrument panel of the motor vehicle or a graphical user interface (not shown).

Now, reference is made 3 taken, being a procedure 200 for testing an OC device 10 and the HCI 8th is described. The OC / HCI test system 80 becomes at block 210 initialized. The control unit 84 receives at block 212 a first exhaust gas temperature value from the first temperature sensor 48 and at block 214 a second exhaust gas temperature value from the second temperature sensor 50 , At block 216 the first exhaust temperature value is subtracted from the second exhaust temperature value to determine a temperature difference value. The control unit 84 leads at block 218 a first check that the temperature difference values with a first threshold 90 compares. If the temperature difference value is greater than the first threshold 90 is at block 220 both the OC device 10 as well as the HCI 8th so conceived that they have passed the first exam and are considered to work properly. A positive test result is sent to the display 110 at block 230 led, and at block 232 checking is stopped. When the temperature difference value is smaller than the first threshold value 90 is, the controller performs 84 a second test.

The control unit 84 receives at block 250 a first oxygen level input from the first oxygen sensor 44 and at block 252 a second oxygen level input from the second oxygen sensor 46 , The control unit 84 directs the first and second oxygen levels through the first and second filters 93 and 94 , and then at block 254 subtracts the second level of oxygen from the first level of oxygen to determine an oxygen level difference. The control unit 84 leads at block 256 the second check out the oxygen level difference with a second threshold 91 compares. When the oxygen level difference is greater than the second threshold 91 is at block 260 the OC device 10 considered erroneous, and the HCI 8th is assumed to be working properly. At block 230 will output to the display 110 directed, which is a faulty OC device 10 indicates. Conversely, if the oxygen level difference is less than the second threshold 91 is at block 262 the HCI 8th considered defective and the OC device 10 considered to work properly. At block 230 will output to the display 110 sent a faulty HCI 8th indicates.

At this point, it should be understood that the test system described in accordance with an exemplary embodiment determines whether both the OC device and the HCI are functioning properly, and if not, based on data provided by on-board oxygen sensors provided a distinction is made between a faulty OC device and a faulty HCI. It should also be understood that the exemplary embodiments utilize both gasoline-based and diesel-based engine systems. Further, it should be understood that the present invention uses existing sensors to test the OC device and HCI, and thus does not require the use of additional sensors. It should also be understood that the first and second temperature values and the first and second oxygen level values may be performed at a plurality of values received from respective first and second temperature sensors and first and second oxygen sensors.

Although the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, the invention should not be limited to the particular embodiments disclosed, but the invention includes all embodiments falling within the scope of the application.

Claims (10)

An oxidation catalyst (OC) / hydrocarbon injector (HCI) testing system comprising: a controller having a first oxygen sensor input configured and arranged to receive a first oxygen sensor value upstream of an oxidation catalyst (OC) device and a second oxygen sensor input configured to supply a second oxygen sensor value downstream of the OC device wherein the controller is configured and arranged to perform a first test based on a difference between the first and second oxygen sensor values to detect a faulty OC device or faulty HCI. The OC-HCI test system of claim 1, wherein the controller further comprises a first temperature sensor input configured and arranged to receive a first exhaust temperature upstream of the OC device, and a second temperature sensor input configured and arranged such a second one Receive exhaust gas temperature downstream of the OC device, wherein the controller is configured and arranged to perform a second test to detect whether the OC device and the HCI operate within desired parameters based on a difference between the first and second exhaust gas temperature. The OC / HCI test system of claim 2, wherein the controller is configured and arranged to perform the second test before the first test is performed. The OC / HCI test system of claim 1, wherein the controller includes a first filter configured and arranged to filter the first and second oxygen values to account for a response time of a first oxygen sensor. The OC / HCI test system of claim 4, wherein the controller comprises a second filter configured and arranged to filter the first and second oxygen values to account for a distance between the first and second oxygen sensors. The OC / HCI test system of claim 1, wherein the controller is configured and arranged to compare the difference between the first and second oxygen sensor values to a threshold to detect a faulty OC device or faulty HCI. Exhaust system for a motor vehicle, comprising: a hydrocarbon injector (HCI) configured to introduce hydrocarbons into the exhaust system; an oxidation catalyst (OC) device located downstream of the HCI; a first oxygen sensor disposed upstream of the OC device; a second oxygen sensor disposed downstream of the OC device; and an oxidation catalyst (OC) / hydrocarbon injector (HCI) testing system comprising: a controller having a first oxygen sensor input operatively connected to the first oxygen sensor, the first oxygen sensor input configured and arranged to receive a first oxygen sensor value and a second oxygen sensor input operatively connected to the second oxygen sensor; second oxygen sensor input configured to receive a second oxygen sensor value, wherein the controller is configured and arranged to perform a first test based on a difference between the first and second oxygen sensor values to detect a faulty OC device or faulty HCI. The exhaust system of claim 7, further comprising: a first temperature sensor disposed upstream of the OC device and a second temperature sensor disposed downstream of the OC device. The exhaust system of claim 7, wherein the controller further includes a first temperature sensor input operatively connected to the first temperature sensor, wherein the first temperature sensor input is configured and arranged to receive a first exhaust temperature and has a second temperature sensor input that is operable with the second temperature sensor wherein the second temperature sensor input is configured and arranged to receive a second exhaust gas temperature downstream of the OC device, the controller configured and arranged to perform a second test based on a difference between the first and second exhaust gas temperatures detect whether the OC device and the HCI are operating within desired parameters. The exhaust system of claim 7, wherein the controller is configured and arranged to compare the difference between the first and second oxygen sensor values with a threshold to detect a faulty OC device or a faulty HCI.

Images